1. Field of the Invention
The present invention relates to a refrigeration apparatus such as, for example, a showcase equipped with a refrigeration system and exemplified by a showcase for displaying articles of fish, greens and the like used as raw materials for vinegared rice ball with sliced raw fish (or greens) thereon or therein or so-called "sushi" in Japanese in a "sushi" bar or shop or the like places.
2. Prior Art
As is well known in the art, the refrigeration apparatus of the above type includes a machine chamber for housing therein a compressor and other machinery, and a display chamber in which a cooling pipe and others are disposed, wherein a coolant such as the cooling air fed from the compressor is expanded and forced to flow through the cooling pipe for cooling and preserving the raw materials for "sushi" disposed within the display chamber. Heretofore, various structures of such refrigeration apparatuses have been proposed and actually employed.
However, each of the refrigeration apparatuses known heretofore is generally of such a structure in which the cooling pipe is disposed within the display chamber, wherein the interior space of the display chamber is cooled under the effect of evaporation of the coolant flowing through the cooling pipe, as is disclosed, for example, in Japanese Patent Application Laid-Open No. 37665/1987 (JP-A-62-37665).
Due to the disposition of the cooling pipe within the display chamber among others, the hitherto known refrigeration apparatuses suffer from many problems mentioned below:
(1) The cooling pipe provides obstacle upon placing or taking out articles in or from the display chamber as well as upon cleaning the interior space of the display chamber;
(2) Because of straightforward evaporation of the coolant within the cooling pipe, moisture contained in the atmosphere within the display chamber is forced to condense to thereby form frost on the outer surface of the cooling pipe, resulting in an adverse environment to the articles being displayed by promoting dryness of the atmosphere within the display chamber;
(3) Upon stoppage of operation, the frost is detached from the cooling pipe to drop onto the articles being displayed. Under the circumstance, continuous operation is required, which in turn makes it difficult to adjust the temperature prevailing within the display chamber, not to say of degraded capability for power saving; and
(4) Because of difference in temperature between the cooling pipe and the interior space of the display chamber, an air flow due to the natural convection takes place, incurring discoloration in the surfaces of fresh food articles under the influence of the air flow.